Yes is your shore power cord 50 (4 prongs) or 30 (3 prongs) amps? If 50 amp you might have lost one leg of power. A 50 amp into a 30 amp (3 prongs) campground outlet might suggest a bad or fried adapter.
If 30 amp plugged into a 30 amp pedestal I would start looking again at your breakers. Also it's possible a GFCI outlet is tripped and these items are downstream of that and therefore affected as well. Can you unplug your microwave and plug it in to a known good outlet using an extension cord? That will tell you if the Microwave is fried or if the outlet lost power.